Home » IPCC Climate Change Report – “Human influence on the climate system is clear”

IPCC Climate Change Report – “Human influence on the climate system is clear”

On Sunday 2 November, the IPCC published its Synthesis Report. This report summarises the Fifth Assessment Report, which was produced by working groups of over 800 scientists and is intended as a guidance document for policymakers.

The report is split into four sections or topics. Topic 1, ‘Observed Changes and their Causes’, outlines the evidence for a changing climate and the impacts of this change. The report states that ‘[w]arming of the climate system is unequivocal’ and that this change can be seen in the fact that the ‘atmosphere and ocean have warmed, the amounts of snow and ice have diminished, and sea level has risen.’ This section of the report also looks at the man made contributions to climate change and states that ‘[h]uman influence on the climate system is clear, and recent anthropogenic emissions of greenhouse gases are the highest in history.’

Topic 2, ‘Future Climate Changes, Risks and Impacts’, assesses the projections for future climate change and its impacts. Under all the emissions scenarios assessed by the IPCC, temperatures will continue to rise over the 21st century leading to further heat waves, extreme precipitation events, the oceans will continue to warm and acidify and sea levels will rise. However, the report also emphasises the fact that these impacts will not be evenly distributed and that the risks of climate change will be much higher for politically, socially and economically disadvantaged people and communities.

“Many of those most vulnerable to climate change have contributed and contribute little to greenhouse gas emissions,” said R.K. Pachauri, Chair of the IPCC. “Addressing climate change will not be possible if individual agents advance their own interests independently; it can only be achieved through cooperative responses.” The section concludes that even if greenhouse gas emissions are reduced, the effects of climate change will continue to be felt for centuries to come.

The third and fourth topic of the report focuses on adaptation, mitigation and sustainable development. Mitigation does come with potential risks, however, the risks do not entail the same widespread and severe impacts as climate change. Limiting warming below 2 °C will require ‘substantial emissions reductions over the next few decades, and near zero emissions of CO2… by the end of the century’. This will pose ‘substantial technological, economic, social, and institutional challenges’. However, Youba Sokona, Co-Chair of IPCC Working Group III stated, “It is technically feasible to transition to a low-carbon economy… what is lacking are appropriate policies and institutions.” Nevertheless, even with adaptation and additional mitigation, global warming will still lead to high risks of severe and widespread impacts.

The final topic of the report emphasises the importance of not relying on a single adaptation or mitigation option, but rather combining multiple measures and creating a link between mitigation, adaptation and other societal objectives. This section outlines the factors that underpin effective adaptation and mitigation, including ‘effective institutions and governance, innovation and investments in environmentally sound technologies and infrastructure, sustainable livelihoods, and behavioural and lifestyle choices.’ Effective adaptation and mitigation also depends on policies at an international, regional, national and sub-national scale.

“We have the means to limit climate change,” said Pachauri. “The solutions are many and allow for continued economic and human development. All we need is the will to change, which we trust will be motivated by knowledge and an understanding of the science of climate change.”

The IPCC Synthesis Report comes ahead of several key climate change talks, the UN Framework Convention on Climate Change meeting in Lima in December 2014 and the UN Climate Change Conference in Paris in 2015. Pachauri said, “I hope this report will serve the needs of the world’s governments and provide the scientific basis to negotiators as they work towards a new global climate agreement.”

You can download the Synthesis Report and the headline summary of the Synthesis Report from the IPCC website.